1. Field of the Invention
The present invention is in the field of insulation support fixtures and the method of making the same.
2. The Prior Art
In the heating and air conditioning industry it is standard practice, in order to minimize heat transfer through the air ducts or conduits to line one or both of the surfaces of the conduit with a lightweight thermal insulating material, such as glass wool urethane foam or the like. Since in many instances foam is applied interiorily of the ducts, access to the foam, after installation of the duct system, is obtained only with great difficulty, requiring disassembly of the system.
It is thus important that the insulating material be dependably secured to the duct.
It is present practice to apply a glue to the interface between the duct and the insulation and, in addition, effect a mechanical connection, such as a headed pin or clip passed through the insulation and secured to the duct. In many instances, the mechanical connection is effected by welding the pin to the surface of the duct. However, in small metal working shops not having access to the welding equipment required, it has been proposed to provide insulation support fixtures in the nature of enlarged thumb tacks, the rear face of the tacks having a pressure sensitive adhesive coating thereon. The fixtures are employed by pressing the adhesive back against a portion of the duct. Thereafter the insulation is emplaced, the sharpened point of the fixture being passed outwardly through the insulation material. Thereafter a washer-like clip is forced over the shank of the pin.
As will be evident from the foregoing, the security of the mechanical connection is dependent upon the security of the adhesive connection between the adhesive layer and duct and also between the adhesive layer, which normally constitutes a double-sided adhesive tape, and the head of the pin.
In the support fixtures heretofore known, connection between the pin and the sheet metal backing is provided by passing a pin having a small head through an aperture in the sheet metal blank and thereafter crimping the metal surrounding the pin tightly against the shank, a double-faced adhesive tape having previously been applied to the back of the metal blank.
Pins of the type described have numerous disadvantages. Since the head of the pin projects slightly beyond the rear surface of the tape, the blank no longer presents an absolutely planar configuration. The bowed or distorted rear face of the device weakens the adhesive connection achieved when the head is pressed against a duct. More significantly, the pin head which projects rearwardly through the tape layer engages directly against the duct, thereby presenting a heat conductive path from the duct through the insulation, with consequent condensation problems. As will be readily recognized, since the conduit defines an air path and is subjected to vibrational stresses, any weakness in the original connection will not only result in a premature separation of the pin from the duct, but will also result in a rattling of the separated pin against the metal face of the duct.